The invention relates generally to fluid controlled valves and more particularly to valves for controlling fluid flow through a flexible tubing.
In many applications of flexible tubing of relatively large diameter, for example in the transmission and use of geothermal gases, it is necessary and desirable to employ valves for controlling the flow of fluid. Installation of a valve element can be accomplished by separating the tubing and inserting a valve between the separated tubing portions. Disadvantages associated with installed line valves of this type include the need to make reliable connections between the tubing and the valve element, and the that fact flow through the tubing must be stopped during installation. An alternative method of flow control for flexible tubing is to install a clamp on the tubing. A clamp is not well adapted to applications where remote control of the valve is desirable, however. For example, to operate a clamp by means of a control cable or other mechanical linkage presents the problem of transmitting an adequate force to reliably close the tubing; however, the clamp pressure must be sufficient to resist being forced open by fluid pressure in the tubing. This conflict in requirements is compounded when the tubing is carrying fluid in different directions from time to time. In such a situation the clamp must be able to resist being forced open from either direction by fluid pressure in the tubing.